# Fecal microbiota transplant trial for peanut allergies > Live situation record from CLSTR: https://clstr.news/situations/fecal-microbiota-transplant-trial-for-peanut-allergies > Updated: 2026-08-10T22:45:31.000Z. Sources: 10. Developments: 3. Researchers from Boston Children’s Hospital and Harvard Medical School conducted a Phase I clinical trial testing oral encapsulated fecal microbiota transplantation (FMT) to treat severe peanut allergies. The study, published in Science Translational Medicine, involved 15 adults who ingested 36 capsules containing frozen microbes from healthy donors. The trial was divided into two phases. In the first phase, 10 participants received a single dose; four months later, three participants demonstrated an increased threshold for peanut reactivity. In the second phase, five participants received antibiotic pretreatment before the FMT to facilitate bacterial colonization. Of these five, three individuals were able to ingest more than four peanuts before experiencing symptoms. Results indicated that the treatment was well-tolerated. Biological analysis suggests the mechanism involves an increase in regulatory T cells, changes in gut bacteria, and higher bile-acid levels, which may help regulate the immune system to promote food tolerance. Building on these findings, recent medical research is exploring the use of advanced biomarkers to move toward a model of personalized precision medicine. A review in Clinical Reviews in Allergy & Immunology highlights the potential of using basophil activation tests and microbiota analysis to help clinicians predict the severity and reaction thresholds of plant-based food allergies. While these developments in microbiome manipulation and biomarker identification show promise, researchers emphasize that larger clinical trials and validations are still required to confirm long-term efficacy and safety. ## Claims - A study involving 15 young adults with severe peanut allergy was conducted. (corroborated by 3 sources) - Participants received oral capsules containing frozen bacteria from healthy donors as a fecal microbiota transplant. (corroborated by 3 sources) - In the first phase, 10 participants received a single dose of 36 capsules; after four months, 3 of them tolerated larger amounts of peanuts before reacting. (corroborated by 3 sources) - In a second phase, 5 participants were pretreated with antibiotics before receiving capsules; 3 of them could ingest more than four peanuts before symptoms appeared. (corroborated by 3 sources) - The study was published in Science Translational Medicine on August 5, 2026. (corroborated by 3 sources) - Responding participants showed higher bile‑acid levels, which may help the immune system tolerate peanuts. (corroborated by 2 sources) - Researchers say larger trials are needed before the therapy can be recommended for food‑allergy treatment. (corroborated by 2 sources) - The study was the first to demonstrate that microbiome-based therapy may improve food allergy in humans. (single source) ## Timeline ### 2026-08-10: Medical research explores microbiome and biomarkers for food allergy treatment New research explores fecal microbiota transplants to increase peanut allergy tolerance and identifies potential biomarkers to enable personalized, precision medicine for plant-based food allergies. 2 sources. https://clstr.news/cluster/medical-research-explores-microbiome-and-biomarkers-for-food-allergy-treatment ### 2026-08-07: Fecal microbiota transplant capsules show promise in treating peanut allergies A small clinical trial found that fecal microbiota transplant capsules helped six of 15 adults with severe peanut allergies tolerate higher levels of peanut protein, potentially via gut microbiome reshaping. 2 sources. https://clstr.news/cluster/fecal-microbiota-transplant-capsules-show-promise-in-treating-peanut-allergies ### 2026-08-05: Boston Children's Hospital trial shows FMT may boost peanut allergy tolerance A small Phase I trial at Boston Children's Hospital suggests fecal microbiota transplantation can increase peanut tolerance in adults with severe allergies by modulating gut bacteria and bile acids. 6 sources. https://clstr.news/cluster/fecal-microbiota-transplant-improves-peanut-allergy-tolerance-in-early-trial --- Cite as: Fecal microbiota transplant trial for peanut allergies. CLSTR, https://clstr.news/situations/fecal-microbiota-transplant-trial-for-peanut-allergies